An al Qaeda spinoff operating near Aleppo, Syria's largest city, last week began a new battle campaign it dubbed "Expunging Filth."

The target wasn't their avowed enemy, the Syrian government. Instead, it was their nominal ally, the U.S.-backed Free Syrian Army.

A band of fanatical al Qaeda rebels are turning their guns on more secular rebels in an attempt to turn the struggle in Syria into a holy war. WSJ's Nour Malas joins the News Hub to explain. Photo: Getty Images

Across northern and eastern Syria, units of the jihadist group known as ISIS are seizing territory—on the battlefield and behind the front lines—from Western-backed rebels.

Some FSA fighters now consider the extremists to be as big a threat to their survival as the forces of President Bashar al-Assad.

"It's a three-front war," a U.S. official said of the FSA rebels' fight: They face the Assad regime, forces from its Lebanese ally Hezbollah, and now the multinational jihadist ranks of ISIS.

Brigade leaders of the FSA say that ISIS, an Iraqi al Qaeda outfit whose formal name is the Islamic State of Iraq and al-Sham, has dragged them into a battle they are ill-equipped to fight.

Some U.S. officials said they see it as a battle for the FSA's survival.

ENLARGE

In recent months, ISIS has become a magnet for foreign jihadists who view the war in Syria not primarily as a means to overthrow the Assad regime but rather as a historic battleground for a larger Sunni holy war. According to centuries-old Islamic prophecy they espouse, they must establish an Islamic state in Syria as a step to achieving a global one.

Al Qaeda militants from central command in Pakistan and Pakistani Taliban fighters have also set up operational bases in northern Syria, people familiar with their operations said.

The spread of ISIS illustrates the failure of Western-backed Syrian moderates to establish authority in opposition-held parts of Syria, some of which have been under rebel control for over a year.

The proliferation of the Sunni jihadists and extremists has brought a new type of terror to the lives of many Syrians who have endured civil war in the north. Summary executions of Alawites and Shiites, who are seen as apostates, attacks on Shiite shrines, and kidnappings and assassinations of pro-Western rebels are on the rise.

Estimates on the size of ISIS range from 7,000 to 10,000 fighters. Fighters from ISIS—though it shares the goal of toppling Mr. Assad's Shiite-linked Alawite regime—have frustrated Sunni communities that until recently embraced the military prowess and social services of Islamist rebels, local residents said.

The FSA's fight with extremists is spurring new rebel calls for Western help, after the U.S. put on hold what had looked like imminent strikes on the Assad regime. Instead, diplomacy has taken over, after a U.S.-Russian deal to disarm Syria's chemical weapons.

A parallel effort continues by Gulf states—and to a much lesser extent by the U.S.—to strengthen select rebel units viewed as moderate, according to Western officials familiar with the arms flow to Syrian rebels.

The FSA's Supreme Military Council, and other rebels who want the U.S. to intervene on their behalf, see the rise of ISIS as an opportunity to firmly separate themselves from al Qaeda militants, whose presence they believe is holding the U.S. back.

This account of the growing influence of ISIS and its backlash is based on interviews with FSA rebels fighting ISIS, Syrian jihadists who have fought alongside the al Qaeda group or are familiar with its operations, and Western officials.

Representatives of ISIS, a group also known as Islamic State of Iraq and the Levant, and in Arabic as al-Dawla, couldn't be reached for this article.

"There's been a real shift in focus [among Syrians in the north]," a Western official working with the opposition said. "A sense of 'We can't get rid of the regime without getting rid of Dawla first.' "

U.S. officials said one reason for the delay in funneling small quantities of light arms to rebels, which began this month, is the difficulty of creating secure pipelines of delivery to intended recipients.

The chaos of the Syrian battlefield, where those fighting to overthrow Mr. Assad sometimes fight side-by-side with those who see Syria as a springboard for global jihad, has compounded U.S. concerns over this process.

U.S. and other Western officials said they were aware of a local backlash and localized FSA counteroffensives against ISIS. They welcomed FSA efforts to draw a line between al Qaeda fighters and the rebels who Western states back.

The extremists pose a threat to the ability of the political opposition, too, to gain legitimacy on the ground and better coordinate with the Free Syrian Army.

In the past half-year, as the Syrian Opposition Coalition, the main opposition body, deliberated over forming what it calls an interim government, extremists have gained ground across the north.

"It's an uphill struggle for the coalition's interim government to establish itself inside Syria in the face of threats from the regime, and extremists, but there is still an opportunity to be missed here," a senior Western diplomat said. "It's still the case that a majority of Syrians are not up for Talibanization. Given a moderate alternative, they will choose that."

The other alternative: A lawless north becomes a launchpad for jihadists, akin to areas of Pakistan and the Arabian peninsula.

"The roots of Waziristan, of southern Yemen have been planted in northern Syria," a Western official working with the opposition said.

The group has moved quickly. In mid-August, ISIS pushed a well-known FSA unit, the Ahfad al-Rasoul brigades, out of the city of Raqqa in northern Syria after tit-for-tat killings and bombings between their fighters.

On Wednesday, clashes broke out in the town of Azaz, near the Turkish border, between ISIS fighters and rebels from an FSA-allied group, leading to some casualties on both sides, opposition activists in the town said. Clashes continued past midnight, activists said.

Along Syria's border with Turkey, ISIS fighters are trying to wrest the four major crossings from other rebel units, in a bid to control supply routes, according to rebels battling the extremists, and Western officials.

In recent weeks, ISIS fighters have adopted a strategy of dropping back—taking rear positions—as rebels with the FSA alliance leave for front lines to fight government forces, allowing ISIS to build a presence in towns and villages left without security or services.

Some Syrians in the villages that dot the Turkish border have changed their lifestyles to dodge persecution by followers of ISIS's fearsome brand of Islamic extremism.

Local men grow beards to pass without scrutiny through ISIS checkpoints. Many Syrian activists and aid workers, wary of their affiliations with Western aid agencies and governments, now say they prefer to work in Turkey and avoid cross-border trips, many border residents and aid workers said.

These jihadists see a long-term mission in Syria. Foreign fighters have begun to move their families to Turkish border areas, locals said.

The trickle of families picked up after the possibility of a U.S. strike on Syrian government targets emerged late last month in response to an Aug. 21 chemical attack near Damascus. U.S. officials said they saw indications the militants hoped they could seize on a U.S. strike to shift momentum against the regime.

As the U.S. threat receded, emboldened ISIS militants ramped up efforts to win local support, said Hamid Ibrahim, a spokesman for FSA leader Gen. Salim Idriss.

"They are telling them: 'We told you that you can't depend on America for freedom. Don't be fooled—you only have us,' " Mr. Ibrahim said.

The Supreme Military Council, led by Gen. Idriss, has been the focus of U.S. efforts to bring a command-and-control structure to rebels—but has now lost to the Islamist extremists most of its ability to operate in some parts of the north.

ISIS fighters recently raided a council arms depot filled with lights weapons and ammunition, funded by the Gulf states and funneled to the council with the guidance of the Central Intelligence Agency, council members said.

From Idlib in the north to Deir el-Zour in the east, Syrian activists are looking for Western help to learn ways to push back against al Qaeda's influence.

In Aleppo and Hama, local rebel police forces are being trained with U.S. funds to put security in the hands of American allies.

The foreign jihadists have become a problem even for some of the hard-line Syrian Islamists who worked most closely with them on the battlefield. One such group is Ahrar al-Sham.

On Sept. 10, a gunfight that broke out at an ISIS checkpoint in Idlib killed a revered leader, Abu Obeida, as he accompanied Turkish and Malaysian relief workers on a distribution mission, unleashing criticism in Islamist rebel circles against ISIS.

ISIS members, posting on social-media networks, said the delegation was stopped because fighters confused the Malaysian flag for the American flag.

They deny intending to kill Abu Obeida, and said they aimed to shoot him in the legs only to keep him from running away after they had ambushed him and stuck him in the trunk of a car.

Gaining Ground

The spread of Iraqi al Qaeda groups in Syria

Late 2011 The Islamic State of Iraq, or ISI, al Qaeda's Iraq branch, moves operatives to Syria to set up a new affiliate, Jabhat al-Nusra.

January 2013 Al-Nusra, led by Abu Muhammad al-Golani, announces itself as an official entity in online videos. In the months that follow, al-Nusra becomes a leading Syrian rebel fighting force, attracting thousands of jihadists, including foreigners. It also provides social services in parts of northern Syria—and ends up designated by Washington as a foreign terrorist organization.

April ISI leader Abu Baker al-Baghdadi changes the name of ISI to Islamic State of Iraq and al-Sham, or ISIS, in an attempt to swallow Jabhat al-Nusra into a broadened entity. Al-Nusra's leader, al-Golani, rejects the plan, pledging allegiance to central al Qaeda chief Ayman al-Zawahiri.

Spring 2013 In the months that follow, the two groups separate. Syrian jihadists leave al-Nusra for ISIS. ISIS begins to attract thousands of foreign fighters to Syria.

June 13 At conference in Cairo of regional Sunni clerics, over 100 prominent religious leaders sign a document urging jihad in Syria; more foreign fighters flock to the civil war.

Aug. 15 ISIS pushes FSA unit the Ahfad al-Rasoul brigades out of the city of Raqqa, after detonating several suicide car bombs, including one that destroyed the brigades' headquarters there.

Sept. 10 A leader of hard-line Islamist group Ahrar al-Sham is killed after a clash at an ISIS checkpoint in Idlib.

Sept. 11 Al Qaeda chief al-Zawahiri urges Islamists fighting in Syria not to work with the secular opposition. He also calls for 'lone-wolf' or small-scale attacks to damage the U.S. economy.

Sept. 11 Syrian government warplanes bomb a field hospital in al-Bab, a town in Aleppo under ISIS control. Residents and FSA fighters respond by attacking the ISIS headquarters in the town.

Sept. 12 ISIS fighters take over a base in eastern Hama including a depot with dozens of rockets, rocket launchers and armored vehicles.

Sept. 13 ISIS's eastern Aleppo unit declares war on its rivals in a campaign it named 'Expunging Filth,' identifying two FSA units by name.

Sept. 18 ISIS and an FSA-allied unit clash in Azaz, an Aleppo town 2½ miles from the Turkish border. An opposition activist in the town said ISIS attacked the unit for trying to obstruct the al Qaeda group from arresting a German doctor working at an Azaz field hospital.

Couldn't happen to a better bunch of IDIOTS who serve the Rothschild/Rockefeller bankers. They were SENT IN to all these sovereign middle-east countries by the US/UK to STIR UP chaos and OVERTHROW the rulers, but when they didn't succeed, they cried out for the countries to be bombed under "cover" of the UN, and the people murdered for their resources, gold, and oil in the name of the Rothschilds/Rockefellers and their central banks. WHO ARE THE SO-CALLED "REBELS"? CIA/ SAS/ Mossad/ Blackwater/ Muslim Brotherhood/ and poor middle-easterners who have been offered a gun and $100 a day by the US/UK to join them.

Every entity in the Syrian civil war will loose. All of the rebel factions will loose. Assad will lose. All foreign nations that provide support will loose. The USA should back off all intervention, present and future. If Obama really has an uncontrollable urge to participate, he should direct humanitarian aid in support of the refugees that had to flee for their lives.

Sort of reminds one of the 30s in China where the Japanese were fighting two different Chinese groups (Nationalists and Communists). The US gave a ton of aid to the Nationalists and took out the Japanese..and who won China..the Communists...

Maybe McCain can parachute into the rebel strongholds and lead them to victory...along with Lindsey...

Sooooooooooooooo, who exactly did John McCain wine and dine with when he was out and about the................what's that phrase again? Oh yes, Freedom Fighters. Yes, that's it. Johnny. Come on Johnny, who were you playing poker with while traveling on our dime? Sooooooooooooooooooo, let's just call it the way it is: It's a Civil War and there's no "good" characters to root for. Surprised? Not one bit.

Those guys look like they are having fun ("Look at the toys we got from the US for free - but their own people can't have them. Those Americans are SO stupid...") ? I wouldn't have my finger on the trigger like that unless I was intending to fire that weapon....

So here we have our precious hard earned tax dollars being spent to "arm rebels in Syria" and we have no idea where those weapons will end up (Sorry John - I don't trust you on this one...)

BUT - we DON"T have enough money to defend our military basis because of the sequester?! We don’t have enough money to take security clearance away from mentally unstable people? You have got to be kidding me?! I haven't been watching the MSM lately (I need a mental break) - I HOPE someone is pointing out these hypocrisies....

I just can't understand why we would want to get involved in this mess. While I do feel for the innocents being killed, both sides hate us and they will still hate us once they are done killing each other. Arming the rebels is just arming another Al Qaeda that will attack us once they finish with Assad (if they win).

This is no surprise--and another reason the US ought not to be involved in any aspect of the Syrian civil war. All these factions are tribal. None of the factions are worth our time; our money; or our armament.

Surprise! Just like Iraq and Afghanistan. Once you're in there, you can't tell friend from foe. Let's not go there again.

The only thing to do with this type of fire is to contain it with fire breaks and watch it burn. Less costly in American lives and treasure and it achieves the same result. In the end, they burn themselves out and everything is destroyed.

I wrote a month ago concerning lessons learned from how Mao Ze-dong took over China. During WW2, Mao instructed his fellow communists to fight the KMT (Chiang Kai Shek) rather than the Japanese, with his goal of eventually taking over China. This is what is happening in Syria. The random event sequence somehow saved the US from getting involved in the military conflicts. It is a good thing!

There is something about politics that drains words of their meaning. Can anyone wielding a machine gun be accurately described as a "Moderate?" Is this not a Monty Pythonesque distinction between the Judean People's Liberation Front and the People's Liberation Front of Judea?

These people have been fighting each other for 1400 years, so don't look for it to stop anytime soon. Look at Afghanistan, Iraq, Libya, Egypt, now Syria...endless infighting. These people are not civilized yet.

This is just more proof that the U.S. should have nothing to do with this quagmire. Let the Syrians work this out themselves. If they start to attack Israel or any other U.S. ally, then we will need to bomb them into oblivion. Until then, we will only stir up a hornets nest.

Which of these 'rebel' groups is communicating telepathically with Senator McCain urging him to arm them? When McCain attaches a wire hanger to the top of his tin foil hat, their messages come in perfectly.

"U.S. officials said one reason for the delay in funneling small quantities of light arms to rebels, which began this month,"

Am I the only one that sees the irony in all this? The same people that blame every gun crime in america on our 2nd amendment right, and the "ubiquitousness" of them, think that the answer to Syria's problem is to send them more guns. One of the few places on the planet that has more than their "fare share".

It is truly astounding.

The same mind reasons: America is too violent, we must git rid of all the guns. Syria is too violent, we must send them more guns.

One thing is certain. These folks in the Middle East have been butchering each other for over 15 centuries and neither a few cruise missiles nor paper treaties will ever change that. Most of the stable governments in the area are, and have been, run by vicious sadist murdering dictators.

With so many monsters always fighting for power, “honor” and/or some religious sect, millions of peace loving people never have a chance to live what we would call normal lives.

Can you imagine McCain as president? We would be nation building in Iran, Syria, Lebanon, Chechnia, etc. at least Barry can claim having done one good thing by keeping the war mongers at bay with their contractors. Fire all the contractors and increase our military. We would save trillions. Same goes with prisons. Is it any coincidence that McCain is the number one recipient of prison contractors largesse?

Great photo of LtGen George S. Patton. I wonder what HE would do in this situation ?? Attack all THREE 'rebel' groups, make it look like they attacked US, and be in Damascus in TWO weeks, perhaps ??? That's what Patton wanted to do with the Russians BUT, Omar told him that the Russians were our 'allies'. And what did we get ??? THE WARSAW PACT and COMMUNIST OPPRESSION for over four decades ......

Correct...great analogy...the US goes in and wacks Assad and the Islamic rebels take over...and the US will probably be stupid enough to do it..after all Israel views Assad as the main threat..not the terrorists..and AIPAC has influence in US policy

totally agree. and under what authorization is our government sending them arms? I do not recall Congress declaring war nor providing Obama with the authority to use military force or provide weapons to Syria. Do impeachment hearings need to commence? Who is going to jail over this?

Don'tcha hate it when both those little devils sitting on either side of your head convince you you're right on both points and then they high-five each other right under your chin? And you can even hear them do it?

Sorry. This number has been disconnected. Go kill each other like you've been doing for 8 thousand years. Go mess with Israel if you want a real butt kicking. They will vaporize you and rid the earth of you're pestilential insignificance.

It's such a big difference when you gas someone as opposed to blowing their heads off. It's good for the economy though. Just like Endless QE and raising debt ceiling for the last 13 years. Throw all the bums out. Rand Paul in 16!

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